Field of the Invention
Embodiments of the present disclosure relate to the technical field of injection molding technology, and in particular to an injection mold for injection molding a sheet component and a device for preparation of a light guide plate.
Description of the Related Art
A conventional injection mold for forming a sheet component e.g., a light guide plate used in the display field by injection molding, is illustrated in FIGS. 1 and 2, wherein FIG. 1 illustrates an injection mold in the prior art for molding a light guide plate 30; and FIG. 2 illustrates a schematic partial enlarged view at an ejector pin of the injection mold as illustrated in FIG. 1. An injection mold for injection molding a light guide plate 30 typically comprises a male mold 10 and a female mold 20 which cooperates with the male mold 10, both of which define collectively therebetween a molding cavity adapted for forming a sheet component therein. After the light guide plate 30 is formed with the injection mold, it is necessary to separate the light guide plate 30 from the male mold 10. In the prior art, as illustrated in FIG. 1 and FIG. 2, the light guide plate 30 is separated from the male mold 10, typically in a manner of pushing inwards the injection mold (e.g., pushing upwards) directly at a bottom portion of the light guide plate 30 by an ejector pin 17. Since the light guide plate 30 has higher optical requirements upon preparation thereof, then it is specified that there should be no tracks formed by pushing upwards with the ejector pin on surfaces of the light guide plate 30. Therefore, as illustrated in FIGS. 1 and 2, in the prior art, the ejector pin 17 may only be provided at a molded gate section 31 which is formed within a runner gate of the injection mold in communication with the molding cavity and integrally connected with the light guide plate 30.
However, in the prior art, as illustrated in FIG. 1 and FIG. 2, before a molded light guide plate 30 is pushed out of a mold cavity between the male mold and the female mold, a gap between the light guide plate 30 and a core insert 15 of the male mold 10 is nearly in a vacuum condition, resulting in a relatively strong adsorption force existing between the light guide plate 30 and the core insert 15 of the male mold 10. Therefore, when the light guide plate 30 is pushed upwards by the ejector pin 17 provided at a lower side of the molded gate section 31, the light guide plate 30 may be deformed to be warped, or even deformed to a degree that may be hard to restore to a flat condition, such that the quality of the light guide plate 30 is degraded. Besides, in a case that there is an excessively large adsorption force between the light guide plate 30 and the core insert 15 of the male mold 10, a breakage may thus be easily incurred at a junction between the molded gate section 31 and the light guide plate 30 under a pushing upwards action of the ejector pin 17, such that the molded gate section 31 is separated and detached from the light guide plate; and once the molded gate section 31 is detached from the light guide plate 30, the light guide plate 30 may not be pushed out of and removed from the male mold 10 only by means of the pushing upwards action of the ejector pin 17, resulting in a shutdown operation required to perform removal and cleaning processes of debris, rather than a normal demoulding process of the light guide plate 30, such that the operation of a production line is interrupted and thus a normal production thereof is influenced.